Upstream unrefined petroleum resources and complex operating environments pose a significant threat to the integrity and safety of gathering pipelines. In this work, we proposed a novelty risk assessment method for gathering pipelines. Specifically, the historical failure data were used to develop the fishbone diagram of hazard factors and quantitatively analyze the primary indexes of internal corrosion failure. The risk assessment method was established combined the KENT method and information entropy theory, including models of failure probability and failure consequence coefficient. Subsequently, The welding institute (TWI) risk classification method was adopted to develop the risk classification calculation method for different areas, combined with the area-level safety design coefficient. Finally, the proposed method was applied to 81 gathering pipelines. Research results showed that the risk assessment method proposed in this paper could meet the real safe operation of gathering pipelines, improving upstream energy security.